Download presentation
Presentation is loading. Please wait.
Published byEthelbert Carpenter Modified over 9 years ago
1
SeaWiFS-based chlorophyll in selekt Chl [mg m -3 ] Sub-decadal oceanic oscillations regulate the north-eastern Atlantic shelf ecosystems Hjálmar Hátún, Payne, M., Sandø, A. and others... Santander, 2011 Blue whiting Sub-decadal oceanic oscillations and blue whiting recruitment
2
Outline The subpolar gyre – marine climate link and blue whiting stock dynamics Can we predict recruitment? – some new ideas on the sub-decadal variability.
3
Subtropical Gyre Subpolar Gyre Labrador Sea convection (Hatun et al., Science 2005) 1. The Subpolar Gyre and the marine climate
4
R I Salinity in the Irminger Current (obs.) Salinity at Rockall (obs.) Gyre index (GI) Record high T and S 1. The Subpolar Gyre and the marine climate Weak. Strong
5
Simulated temperature Cold Warm 1. The Subpolar Gyre and the marine climate Large mid-1990s changes!
6
Blue whiting Blue whiting: Spawning-feeding distributions/migrations Feeding Spawning Mackerel Herring
7
Stor endringer i kolmule bestanden Largest fishery in the North Atlantic! A threefold blue whiting stock size increase SST (in Rockall Areal) Stock size (<- shifted 3 years)
8
Warm (1998-2003) Cold (1990-1996) Spatial Shift (Blue whiting catches – all nations) 1997 Spawning distribution: (Hátún et al. 2009, CJFAS) Post-spawning migration: (Hátún et al. 2009, PIO)
9
So what about blue whiting recruitment?
10
Need to understand the processes (Payne et al., 2011, In Press) North Atlantic Sub-polar gyre Recruitment Gyre index and recruitment not significantly correlated Atmospheric forcing
11
Wind stress curl UK Green- land Anticyclonic (Curl <0) Wind stress (ws) - arrows (NCAR/NCEP) Curl (ws) [N/m ] 2 0 Cyclonic (Curl >0) 2. Atmosphere-gyre details
12
WSC = 0 Subtropical Gyre Subpolar Gyre 2. Atmosphere-gyre details
13
Subpolar Gyre ”Inter-gyre region” ’Window’ 2. Atmosphere-gyre details WSC = 0 Subtropical Gyre
14
’Navidad’ ”Inter-gyre region” Subpolar Gyre 2. Atmosphere-gyre details
15
Recruitment and wind stress curl 2. Recruitment Spain R Recruitment Vs. WSC
16
Recruitment and wind stress curl
17
Northward transport Improved Recruitment?
18
Sea surface height and marine climate Warmer 3. Monitoring with altimetry
19
Gyre Mode Spatial pattern (Updated from Hakkinen and Rhines, 2004) 3. Monitoring with altimetry Time series (gyre index)
20
Transport anomalies of source waters Western source Eastern source 3. Monitoring with altimetry ~ 7 Sv (Pingree, 2002)
21
An along-Continental Slope perspective (Data availability) Decompose onto a S-axis Porcupine (Hátún et al. 2009, CJFAS) 2. Hydrographic Pulses
22
Porcupine Shetland Salinity @ 300m 2. Hydrographic Pulses Salinity
23
Porcupine Shetland Salinity @ 300m 2. Hydrographic Pulses Salinity, currents Weaker NAC
24
Porcupine Shetland Salinity @ 300m 2. Hydrographic Pulses A new boom? Salinity, currents and recruitment
25
So is the recruitment predictable? Not with certainty - But certainly not if the marine climate is ignored I ’predict’ that the 2009 year-class will be strong
27
3. Monitoring with altimetry Transport anomalies of source waters
28
3. Monitoring with altimetry Transport anomalies of source waters and blue whiting recruitment
29
Salt-pulses and blue whiting recruitment 2. Recruitment Porcupine Shetland
30
So what about recruitment? Bad recruitmentGood recruitment (Hátún et al., 2009, CJFAS)
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.